ATM网中VPN业务的设计与实现

本文分析了ＡＴＭ网中基于ＶＰ和基于ＶＣ两种层次的ＶＰＮ业务的特点,提出了ＶＰ子层的ＶＰＮ业务的设计,并讨论了一种基于ＴＭＮ和ＣＯＲＢＡ的ＶＰＮ管理系统的实现方案。     

IP VPN安全保证技术

ＶＰＮ是在公用数据网基础上架构专用网的技术。若公用网为ＩＰ网络，则称为基于ＩＰ的ＶＰＮ。为了达到专用网的目的，必须保证ＶＰＮ资源的独立性，即资源在一般情况下不允许其他ＶＰＮ或者不是该ＶＰＮ用户的网络成员使用。另外，ＶＰＮ的安全性是组建ＶＰＮ的关键因素，即ＶＰＮ用户的信息不应流出ＶＰＮ的范围；而外部的用户在一般情况下也不能访问ＶＰＮ信息。下面介绍ＶＰＮ的主要技术。 一、VPN的分担控制 ＶＰＮ可由公司自己或ＩＳＰ经营，形成基于用户端设备（ＣＰＥ）或基于网络的ＶＰＮ。基于ＣＰＥ的ＶＰＮ的性能综合在大量…     

虚拟专用网络技术

对ＶＰＮ的基本概念作简要介绍后,着重分析了ＶＰＮ的三种典型的应用方式,即Ｉｎｔｒａｎｅｔ ＶＰＮ,远程接入ＶＰＮ和Ｅｘｔｒａｎｅｔ ＶＰＮ,并对现有的一些ＶＰＮ技术进行了总结,提出了一个一般的ＶＰＮ体系结构模型。     

企业VPN构建方案

本文以中山市财政局企业ＶＰＮ的构建实例，详细讨论了ＶＰＮ技术在企业建网方面的实际应用，提出适合于利用公众网组建内部网的整套解决方案。     

ECV与PVS技术在InP系列多层异质外延材料测试中的应用研究

ＥＣＶ与ＰＶＳ是目前国内外半导体多层异质材料测试中的一种先进技术。利用ＰＮ４３００半导体分布测绘仪和ＰＮ４３５０光压谱仪，测试了ＩｎＰ系列多种异质材料的Ｎ－Ｗ、Ｃ－Ｖ、ＰＶＳ、Ｉ－Ｖ特性。分析和讨论了德拜长度限制、阳极化染色，表层测试点散乱、ＰＶＳ显示次序与光响应层最小厚度限制，Ｃ－Ｖ曲线不连续等问题。     

IP VPN业务管理的技术要求

ＩＴＵ的 ＶＰＮ标准 ＩＴＵ—Ｔ ＳＧ１３在２０００年１１月的会议上宣布了两个基于网络的ＩＰＶＰＮ草案： Ｙ． ＩＰ ＶＰＮ． Ｏ与 Ｙ． ＩＰＶＰＮ． １。 Ｙ．ＩＰ ＶＰＮ． ｌ是基于ＭＰＬＳ的ＩＰ ＶＰＮ技术要求,在业务提供商的网络中采用ＩＰ技术,而在骨干网中采用ＭＰＬＳ,其参考模型说明业务提供商要提供ＩＰ ＶＰＮ业务需要两类设备,即边缘设备与骨干设备。ＩＰ ＶＰＮ业务只能在边缘设备上提供,而对于骨干设备,ＩＰ ＶＰＮ业务是透明的。ＩＰＶＰＮ主要的业务要求是：（１）多家厂商的设备应能互通;（２）应具备业务…     

基于MPLS的VPN的实现

主要介绍基于ＭＰＬＳ的ＶＰＮ的实现,着重介绍了传统ＶＰＮ面临的困难、建设ＭＰＬＳ－ＶＰＮ的可能性以及ＭＰＬＳ－ＶＰＮ的实现方案。     

IP VPN技术及广东电信MPLS VPN的试验(1)

１ＩＰＶＰＮ技术概述ＶＰＮ（ＶｉｒｔｕａｌＰｒｉｖａｔｅＮｅｔｗｏｒｋ）即虚拟专网 ,是指一种利用公网的网络资源 ,为特定用户提供类似于企业专网的服务。在ＶＰＮ用户看来 ,好象是通过一个本企业的专网进行通信 ,而实际上该专网完全是构建在公网的基础上的 ,只不过提供了专网与公网的相对隔离。对企业而言 ,使用ＶＰＮ大大节省了企业专网建设中资金和人力资源的投入 ;对网络运营商而言 ,利用ＶＰＮ可以将网络服务更好地集中起来 ,使客户对运营商的依赖性不断增强。１．１ＩＰＶＰＮ的应用实施要求ＩＰＶＰＮ则是指利用公共ＩＰ网的网…     

我国IPVPN技术及广东电信MPLSVPN的试验[2]

３广东电信ＭＰＬＳＶＰＮ商用网试验广东是全国经济较发达的省份之一 ,市场对通信业务的需求也是走在前列的。广东电信ＩＰ骨干网经过几年的快速发展 ,已基本具备了宽带业务传送平台的条件。无论是从市场需求还是从网络条件看 ,广东电信在ＩＰ网上开展ＭＰＬＳＶＰＮ业务的时机都已经成熟了。为了进一步掌握ＭＰＬＳＶＰＮ运营中所涉及的技术、业务管理等问题 ,更好地提供ＭＰＬＳＶＰＮ业务 ,广东电信在省内组建了ＭＰＬＳＶＰＮ商用试验网 ,进行了ＭＰＬＳＶＰＮ业务的商用实验。３．１ＭＰＬＳＶＰＮ商用试验网组网原则广东省ＭＰＬＳＶ…     

IP VPN—基于IP网络的虚拟专用网

ＩＰ ＶＰＮ能为用户在ＩＰ网络之上构筑一个安全可靠、方便快捷的企业专用网络，并为企业节省资金。本文从ＩＰ ＶＰＮ的概念、分类、组建ＩＰ ＶＰＮ的隧道技术，以及在ＶＰＮ上传送的数据的安全性保证等几个方面介绍了ＩＰ ＶＰＮ技术。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks